Lock nuts which can be threaded onto a keyed spindle and locked into an adjusted position are well known. Among the best known applications is the wheel bearing nut which is tightened to a given result such as a light drag, and is then locked in place. Conventional nuts are usually tightened, and then backed off to the next suitable alignment position for a cotter key. However, they are not self-locking, and depend for their locking action upon the cotter key. Without the cotter key, the nut can vibrate loose. If the cotter key fails, the nut can come loose.
To overcome the disadvantages of such conventional nuts, efforts have been made to provide nuts which after being tightened have locking elements which must be released before the nut can be turned off the shaft. Examples of such nuts are Greenwood U.S. Pat. Nos. 3,581,609 and 3,705,524; and Wing U.S. Pat. Nos. 3,851,690 and 3,942,570.
The efforts to overcome the disadvantages of the cotter-keyed nuts have themselves involved problems that have retarded the acceptance of a good idea. Among the problems is the need always to have a special tool whenever the nut is to be loosened or tightened. Field repairs without the tool are not feasible, and this is a definite disadvantage. A nut according to this invention can be tightened down or loosened with any torque tool which can engage it, but it is held against loosening, unless a sufficient torque is directly applied to a specific part of the nut, which can be done with many types of field tools. This specific part is held against loosening except by those direct forces.
Another object of this invention is to provide a lock nut assembly which, while it is readily assembled, thereafter is an inseparable assembly, which precludes the possibilities of omitting parts, or of misorienting separable parts.
An optional object of the invention is to provide a lock nut which is easier to tighten than to release, thereby improving the self-locking feature of the device.